At a meeting with Mr Muallem shortly before the foreign minister's speech, Mr Ban "raised in the strongest terms the continued killings, massive destruction, human rights abuses, and aerial and artillery attacks committed by the government", his spokesman said.

Analysis

By Sebastian UsherMiddle East analyst, BBC News

No-one expected anything new from the Syrian foreign minister's speech to the UN and nothing new was offered.

His accusations against the key countries supporting the uprising followed a formula Damascus has been sticking to for months.

The only change was in the language.

Mr Muallem said they were all simply backing terrorists, while using what he described as "unprecedented media provocation" aimed at igniting religious extremism.

None of these countries has officially confirmed it is supplying weapons to the opposition, but in one form or another they have been trying to ensure the rebels are better armed.

As the conflict draws in more outside fighters - including Islamic militants - the Assad government is hoping its now ritual justification that it's battling terrorists and extremists will carry more weight.

Certainly, Mr Muallem's talk of reform won't as far as the opposition is concerned. It has long rejected any such offers as too little, too late.

The United States and France along with several regional countries had undermined peace efforts, supplying rebel groups with arms and money, the Syrian foreign minister told the UN.

"Permanent members of the [UN] Security Council who have launched wars under the excuse of combating terrorism [are] now supporting terrorism in my country without any regard to United Nations resolutions."

Mr Muallem said it was no surprise that the Security Council had failed to condemn rebel bombings as some of its members supported such acts.

The BBC's Barbara Plett said his address was a very strong expression of Damascus's position, that it is facing a foreign conspiracy to execute regime change.

The general feeling at the UN, our correspondent says, is that the Syrian government bears primary responsibility for the continuing conflict although there is a difference of opinion over how much criticism should be levelled at the opposition.

'Ambush'

During the day, reports emerged of further violence in Syria carried out by both sides.

A UK-based activist group said 18 soldiers were killed in a rebel ambush and 30 people were feared dead in an air strike by Syrian armed forces on the north-western town of Salqin.

An armed forces convoy was ambushed on the main road from Homs to Palmyra in central Syria, according to the Syrian Observatory for Human Rights.

Buses, lorries and cars were targeted by a series of improvised explosive devices (IEDs), it said. A prominent activist organisation reporting incidents in the Syrian conflict, the group says its reports are impartial, although its information cannot be independently verified.

Image caption
Fierce clashes have continued in Syria's second city Aleppo

Close to the Turkish border in the north-west, barrel bombs were dropped on the town of Salqin, activist network the Local Co-ordination Committees said.

A number of buildings were hit and unverified footage posted on the internet showed badly burned bodies. Several of the victims were children.

In one video, a man is seen shouting that his son has been killed. In another, the bodies of three children are described as being from the same family.

Aleppo battle

Days after rebel forces declared they were launching a campaign to drive government forces out of Syria's second city Aleppo, the battle there is still raging.

Rebels and armed forces were said to be involved in fierce clashes in Aleppo's famed ancient market or souk.

Hundreds of stalls in the souk have been destroyed by a fire that began on Friday and continued the following day.

Aleppo's 13th Century citadel and its Old City, complete with a medieval covered market, is one of six Unesco world heritage sites in Syria.

Speaking earlier to Beirut-based TV channel al-Mayadeen, the Syrian foreign minister accused the United States of "inventing" a problem surrounding his country's chemical weapons.

Damascus officials have recently acknowledged the existence of a stockpile of chemical weapons and US Defence Secretary Leon Panetta said last week that Washington had some concerns about the security of Syria's chemical and biological weapons sites.

However, Mr Panetta acknowledged the major sites were secure.

"Talk of chemical weapons in Syria is fabricated by the US administration," Walid Muallem said.